The present invention relates to an apparatus for performing a predetermined process including etching and deposition for a target object, such as a semiconductor wafer or an LCD substrate by using a plasma generated by discharge.
In a process of manufacturing, e.g., a semiconductor device, a plasma is generated in a processing vessel to perform various plasma processes including etching for a target object such as a semiconductor wafer in this plasma atmosphere. FIG. 11 is a schematic view showing the arrangement of a conventional plasma etching apparatus. In the apparatus of this type, upper and lower electrodes 12 and 14 are arranged to oppose each other in a processing chamber 10, as shown in FIG. 11. A plurality of processing gas spouting holes 18 are formed in the lower surface (i.e., a surface opposing the target object) of the upper electrode 12. An evacuation system 22 is connected to the lower side of the processing chamber 10 via a baffle plate 20.
In etching, a processing gas is supplied to the processing chamber 10 through the spouting holes 18 while evacuating the processing chamber 10. An RF power is applied from an RF power supply 16 to the lower electrode 14 (in some cases, an RF power is also applied to the upper electrode 12) to convert the processing gas into a plasma. By the plasma generated in this manner, a target object W is etched.
In recent years, the capacity of the processing chamber increases along with increases in diameter and size of the target object, requiring a higher effective exhaust rate. However, owing to the conductance of the baffle plate 20 for preventing the plasma from entering the evacuation system, a satisfactory effective exhaust rate cannot be obtained only by increasing the capacity of the vacuum pump of the evacuation system.
The processing chamber 10 is constituted by assembling a plurality of parts 10a to 10d. For this reason, even if the conductivity between the respective parts 10a to 10d is improved as much as possible, the potentials (V1 to V4) of the respective parts 10a to 10d are different. As a result, the plasma is difficult to be confined in the processing space (above the target object) within the processing chamber. This problem is becoming more serious as the diameter and size of the target object increase.
The top plate of the processing chamber constituting the upper electrode 12 is freely openable. By opening this top plate, the inside of the processing chamber can be maintained. However, when the inner wall of the processing chamber is damaged, its repair is very difficult to perform.
To optimize the processing apparatus for each process, the processing gas, the plasma, and the flow of an exhaust gas or the like in the processing chamber must be controlled in accordance with each process. More particularly, parameters such as the flow rate of the processing gas to be supplied to the processing chamber, the diameter of the gas supply hole, the size of the gas supply region, the number of exhaust holes, and the exhaust amount of exhaust gas are desirably adjusted, as needed. However, adjustment of the parameters for each process is very cumbersome, resulting in an increase in initial cost.